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Smokedaddy
Joined: 07 Oct 2006
Posts: 1221
Location: Phoenix, Arizona
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 Posted: Mon Feb 12, 2018 4:42 pm Post subject: Scalpel vs double-edge razor |
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Someone here was discussing MTF Mapper and using a razor blade for a knife edge test. I mentioned that I *thought* a Scalpel blade was sharper and probably even smoother than a razor blade. Of course then we need to define what sharp means. <g> Plus I thought the physical edges were the same on a razor blade, X-ACTO type blades and Scalpels. Boy was I completely wrong! A razor blade is completely different.
Another one of my hobbies is extreme paper cutting. I use 18 lb acid free archival paper. Normally I use a #11 X-ACTO knife "blades" exclusively. Sometimes #11 Excel brand double honed blades and sometimes X-ACTO X-LIFE blades. I go through a TON of blades on a typical cutting. They dull rather quickly and the tips break easily. Then I tried Swann-Morton carbon steel #11 surgical blades. They are a LOT more expensive per blade but lasted a LOT longer (cutting wise). I also started to sharpen them myself BUT I haven't photographed one after I sharpen it. That will be a interesting image to see. I know photographing a razor blade isn't ground shattering news, Charles did it long ago. Personally I was amazed to find out that a Scalpel blade is more like a saw compared to a razor blade. Thought maybe you may find that interesting as well, maybe not either.
-JW:
Last edited by Smokedaddy on Mon Feb 12, 2018 5:37 pm; edited 1 time in total |
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ChrisR
Site Admin
Joined: 14 Mar 2009
Posts: 8173
Location: Near London, UK
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| Posted: Mon Feb 12, 2018 5:26 pm Post subject: |
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A heavily-accented Afrikaaner surgeon once greeted me as an emergency patient with, "We got da nahs blunt scalpel for you". (I also asked if he could patch me up and send me home - "Yaah we could do dat, if you don't mahnd travelling in a box".)
He wasn't joking. I understand that surgeons use "blunt" scalpels to leave rough edges to promote better healing. Scalloped-edge blades do cut some materials better than plain, too.
I see that the "Feather" blades are recommended for microtomes and vibrating microtomes, by the way.
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Chris R |
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Smokedaddy
Joined: 07 Oct 2006
Posts: 1221
Location: Phoenix, Arizona
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| Posted: Mon Feb 12, 2018 5:33 pm Post subject: |
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| ChrisR wrote: | | I see that the "Feather" blades are recommended for microtomes and vibrating microtomes, by the way. |
I was reading a thread on another forum where they tested several dozen razor blades (SEM) and by far the Feather was the sharpest.
I would buy a vintage type microtome in a heatbeat if I knew more about them (missing parts etc.).
-JW |
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ChrisR
Site Admin
Joined: 14 Mar 2009
Posts: 8173
Location: Near London, UK
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| Posted: Mon Feb 12, 2018 5:44 pm Post subject: |
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I have 4 or 5. One of them draws the blade across the specimen as the specimen goes down. It's an old AO I think.
The whole embedding, fixing, staining & mounting performance is something I'll get to if I ever have the space and time!
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Smokedaddy
Joined: 07 Oct 2006
Posts: 1221
Location: Phoenix, Arizona
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| Posted: Mon Feb 12, 2018 6:01 pm Post subject: |
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| ... well I'm living the dream so I have lots of spare time and use every minute of it. |
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rjlittlefield
Site Admin
Joined: 01 Aug 2006
Posts: 19549
Location: Richland, Washington State, USA
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| Posted: Mon Feb 12, 2018 9:26 pm Post subject: Re: Scalpel vs double-edge razor |
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I was glad to see the pictures of cutting edges, because I've been looking at those lately myself. Stanley single-edge blades are really crude. Maybe I can get one photographed sometime...
| Smokedaddy wrote: | | Another one of my hobbies is extreme paper cutting. |
One word: WOW! 
I immediately called my wife over to look at that last image. We're in awe.
--Rik |
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nanometer
Joined: 30 Apr 2016
Posts: 167
Location: Tucson, AZ
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| Posted: Mon Feb 12, 2018 9:55 pm Post subject: |
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Those paper cuttings are amazing. Mike T showed me the one you did of the GMT--phenomenal. Me, I'd buy a paper laser cutter as patience is not something I have a lot of  I suppose programming the laser cutter might take just as much time as actually cutting the design, but then you could make duplicates easily. |
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Smokedaddy
Joined: 07 Oct 2006
Posts: 1221
Location: Phoenix, Arizona
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| Posted: Tue Feb 13, 2018 10:02 am Post subject: |
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| nanometer wrote: | | Those paper cuttings are amazing. Mike T showed me the one you did of the GMT--phenomenal. Me, I'd buy a paper laser cutter as patience is not something I have a lot of I suppose programming the laser cutter might take just as much time as actually cutting the design, but then you could make duplicates easily. |
Thanks for the comment. I actually made that Giant Magellan Telescope cutting for Mike, just haven't got around to sending it to him. I did it twice as the first one wasn't as intricate. BTW, for me the feathers are the hardest.
Actually programming a laser is extremely simple and takes only a few seconds and is software driven (not that you can't adjust or play with the G-Code). Just like a 3D printer, more or less plug and play. I've actually looked into buying something like a Glowforge laser printer but the price is out of my budget ($4K entry level). If I wasn't retired I'd buy one in a heartbeat.
On another note, manually cutting takes skill/dexterity, builds patience and is a art form. I have a strong Architectural manual drafting background from the days when we used ink and drew on mylar with rapidograph pens. Even drew Architectural renderings by hand (water color or felt type markers) and modeled using cardboard/chipboard/posterboard. <g> In those days a particular Architect had his 'own style' of lettering that everyone in the office mimicked too. BTW I'm not against using any CAD software, Nurbs modeling, ray tracing or CNC type machines. I have those skills too.
Not all of the paper cuttings are my designs but I am responsible for cutting them. I don't sell any of my cuttings. They're only for my personal enjoyment. I have made several cuttings for my grandkids and family members but that's it. As a matter of fact paper cuttings were my Christmas gifts this year. I spend about 6 months cutting. I have about 50 plus hours in a typical 8x10 complex paper cutting. I use a Brightech LED 3x magnifier.
-JW: |
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Smokedaddy
Joined: 07 Oct 2006
Posts: 1221
Location: Phoenix, Arizona
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| Posted: Tue Feb 13, 2018 10:11 am Post subject: Re: Scalpel vs double-edge razor |
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| rjlittlefield wrote: | I was glad to see the pictures of cutting edges, because I've been looking at those lately myself. Stanley single-edge blades are really crude. Maybe I can get one photographed sometime...
| Smokedaddy wrote: | | Another one of my hobbies is extreme paper cutting. |
One word: WOW!
I immediately called my wife over to look at that last image. We're in awe.
--Rik |
Thanks Ric ... on another note, the scalpel blade also appears to be wavy? I couldn't nail the focus to my satisfaction. I was using my Nikon MM-11 with a Nomarski DIC setup (which I am by no means an expert at using). Any suggestions on why I couldn't nail the 'edge' focus wise?
-JW: |
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Smokedaddy
Joined: 07 Oct 2006
Posts: 1221
Location: Phoenix, Arizona
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| Posted: Tue Feb 13, 2018 11:03 am Post subject: |
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Update:
Seems like I'm showing my stupidity once again. I don't think the image I posted above is the edge of the scalpel blade and rather the start of the grind. Well see. <duh>
-JW: |
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Smokedaddy
Joined: 07 Oct 2006
Posts: 1221
Location: Phoenix, Arizona
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| Posted: Tue Feb 13, 2018 12:42 pm Post subject: |
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... duh ... totally embarrassed, o'well. I had the illumination wrong with my MM-11 setup. Here's what the scalpel blade 'edge' really looks like. I was wondering how in the world was I able to sharpen the saw-tooth image I posted. 
-JW: |
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Smokedaddy
Joined: 07 Oct 2006
Posts: 1221
Location: Phoenix, Arizona
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| Posted: Tue Feb 13, 2018 2:14 pm Post subject: |
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Here's an updated Feather (brand) razor blade image.
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rjlittlefield
Site Admin
Joined: 01 Aug 2006
Posts: 19549
Location: Richland, Washington State, USA
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| Posted: Tue Feb 13, 2018 2:52 pm Post subject: |
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I'm surprised to see so much debris or corrosion on the scalpel blade. Is this a used blade?
--Rik |
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Smokedaddy
Joined: 07 Oct 2006
Posts: 1221
Location: Phoenix, Arizona
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| Posted: Tue Feb 13, 2018 3:04 pm Post subject: |
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| rjlittlefield wrote: | I'm surprised to see so much debris or corrosion on the scalpel blade. Is this a used blade?
--Rik |
No, brand new. It's a non-sterile carbon steel surgical blade. They come in a sealed foil packet with 5 wrapped blades inside.
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Smokedaddy
Joined: 07 Oct 2006
Posts: 1221
Location: Phoenix, Arizona
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| Posted: Tue Feb 13, 2018 3:11 pm Post subject: |
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Here's the Feather blade at 40x. It's a PMAX stack. I'm not sure what the somewhat blurry areas are or IF it's just how it is. Haven't done the scalpel blade yet.
[Edit AdminCR
New thread started for Equipment queries at Epi lighting using a Nikon UM-2 Measurescope ] |
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